Self-experimentation refers to the very special case of single-subject scientific experimentation in which the experimenter conducts the experiment on him- or herself. Usually this means that the designer, operator, subject, analyst, and user or reporter of the experiment are all the same. It is a special case of single-subject research.
The earliest example of self-experimentation may go back to 605 BCE when Daniel and several other Jewish captives of Nebuchadnezzar were offered positions in the government and a diet of the king's own rich meats and wines. Refusing to violate the Jewish dietary laws, they declined the food and asked for a diet of legumes and water instead. The officials had a serious concern that such a limited diet might be unhealthy so Daniel offered to conduct a "clinical trial" (of sorts). He conducted a diet study as a self-experiment (along with three others: Hananiah, Mishael, and Azariah). After 10 days on the abstemious diet, the subjects appeared even healthier than the controls eating the king's food and they were allowed to continue. Details of the Bible stories can be found in Wikipedia, on the web and elsewhere. There is an interesting evaluation in the context of clinical trials and program evaluations in: David E.K. Hunter, "Daniel and the Rhinoceros", Evaluation and Program Planning Volume 29, Issue 2, May 2006, Pages 180-185 (Program Capacity and Sustainability). Link - DOI
Sanctorius of Padua provides another early documented case of self-experimentation—living on a balance for 30 years in the early 17th century, weighing himself, his daily food, liquids, and combined excretions, leading him toward the discovery of metabolism.
Human scientific self-experimentation principally (though not necessarily) falls into the fields of medicine and psychology, broadly conceived. Self-experimentation has a long and well-documented history in medicine which continues to the present. In psychology, the best known self-experiments are the memory studies of Hermann Ebbinghaus, establishing many basic characteristics of human memory through tedious experiments involving nonsense syllables.
Recently, Dr. Seth Roberts and Dr. Allen Neuringer have advocated the broader use of self-experimentation, arguing that its low-cost and ease (compared to traditional large-sample experiments with human subjects) facilitate conducting a very large number of experiments, testing many treatments and measuring many things at once . This allows considerable trial and error and can lead to the generation and testing of many ideas. Self-experimentation provides superior evidence to mere anecdotal evidence, because the entire experimental is explicitly designed to test a hypothesis, but is subject to observer bias. Self-experimentation could be considered a useful adjunct to large-sample experiments in scientific research.
The self-experimental approach has long and often been applied to practical psychological problems. Benjamin Franklin recorded his self-experiment of successively devoting his attention for a week to one of thirteen "Virtues", "leaving the other Virtues to their ordinary Chance, only marking every Evening the Faults of the Day." In Self-change: Strategies for solving personal problems, M. J. Mahoney suggested that self-experimentation be used as a method of psychological treatment. He recommended that clients be taught basic scientific methods, in order that the client become a "personal scientist."
Until recently, it was common practice among synthetic chemists to taste newly prepared compounds. The purpose was to provide an additional characteristic for identification, taking advantage of the selective chemical receptors that form this sense. However, as one might guess, this practice also led to numerous fatalities and near-fatalities. Surprisingly, it was not recognition of the risk of this self-experimentation that led to its extinction, but rather the advent of instrumentation capable of exacting physical characterization of compounds (particularly spectrometers with infrared, ultraviolet, NMR and mass selectivity). The routine tasting of new compounds by chemists of bygone times is, in fact, the main source of knowledge of the human toxicity for certain chemicals.
This practice had positive and negative aspects. It probably contributed to the death of Carl Wilhelm Scheele from apparent mercury poisoning. Joseph Priestley discovered soda water while experimenting with carbon dioxide and tasting the results. Dr. Albert Hofmann discovered the psychedelic properties of LSD by accidentally absorbing it—and later intentionally ingesting it—in a self-experiment.
Several popular and well-known sweeteners were discovered by deliberate or sometimes accidental tasting of reaction products. Sucralose was discovered by mishearing the instruction to "test" the compounds as to "taste" the compounds. Fahlberg noticed a sweet taste on his fingers and associated it with his work in the chemistry labs at Johns Hopkins; out of that taste test came Saccharin. Cyclamate was discovered when the chemist who was working to make anti-fever medications noticed a sweet taste on his cigarette that he had set down on his bench. Aspartame was also discovered accidentally when chemist Schlatter tasted a sweet substance that had gotten onto his hand. Acesulfame potassium is another sweetener discovered when a chemist tasted what he had made.
Leo Sternbach, the inventor of Librium and Valium, tested chemicals that he made on himself. In an interview, "He said that he used to test his drugs on himself. “I tried everything. Many drugs. Once, in the sixties, I was sent home for two days. It was an extremely potent drug, not a benzodiazepine. I slept for a long time. My wife was very worried.”
JBS Haldane, a notable British biologist, is yet another example of a scientist who conducted experiments upon himself. Haldane was a keen experimenter, and was more than willing to expose himself to danger in order to obtain the desired data. One such experiment involving elevated levels of oxygen saturation triggered a fit which resulted in him suffering crushed vertebrae. In his decompression chamber experiments, Haldane and his volunteers suffered perforated eardrums, but, as Haldane stated in What is Life, "the drum generally heals up; and if a hole remains in it, although one is somewhat deaf, one can blow tobacco smoke out of the ear in question, which is a social accomplishment."
After failed attempts to infect piglets in 1984, Barry Marshall drank a petri-dish of the Helicobacter pylori from a patient, and soon developed gastritis, achlorhydria, stomach discomfort, nausea, vomiting, and halitosis, fulfilling Koch's postulates. The results were published in 1985 in the Medical Journal of Australia, and is among the most cited articles from the journal. He was awarded the Nobel Prize in Physiology or Medicine in 2005.
Charles Dalziel studied the effects of electricity on animals and humans, and wrote The Effects of Electric Shock on Man, a book in which he explains the effects of different amounts of electricity on human subjects. He carried out experiments on human subjects including himself. He also invented the ground-fault circuit interrupter or GFCI, based on his understanding of electric shock in humans.
In 1998 a British scientist, Kevin Warwick, became the first human to test an RFID as an implant to control surrounding technology. In 2002 he went on to have an array of 100 electrodes fired into the median nerve of his left arm during a 2-hour neurosurgical operation. With this implant in place, over a 3-month period, he conducted a number of experiments including the first direct electronic communication between the nervous systems of two humans.
Examples in classic fiction include the tales of The Invisible Man and Dr. Jekyll and Mr. Hyde. In each case the scientist's unorthodox theories lead to permanent change and ultimately to self-destruction.
Self-experimentation is a common trait amongst mad scientists and evil geniuses in more contemporary fiction and is part of the creation story of many comic book supervillains, and some superheroes. For example, the Spider-Man villain, The Lizard, was Dr. Curt Connors, who lost his arm in a war (other versions vary), and experimented with reptilian DNA to try to grow it back; but the therapy caused him to mutate into a half-human-half-reptile creature. On the hero side, the Fantastic Four were created when they were testing Reed Richards new prototype rocket and were exposed to cosmic rays, giving them super powers. Other cases include the Man-Bat, the Ultra-Humanite, the Green Goblin, and the animated Justice League version of Cheetah.
- "Self-Experimenters Step Up for Science. Eight stories of do-it-on-yourself discovery illuminate the promise and perils of a sample size of one". Scientific American. March 10, 2008.
- Seth Roberts and Allen Neuringer. Self-Experimentation in Handbook of Research Methods in Human Operant Behavior.
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- "Little Helper", Nick Paumgarten, The New Yorker, June 16, 2003, pp. 71-72. 
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- Van Der Weyden, Martin B; Ruth M Armstrong; Ann T Gregory (2005). "The 2005 Nobel Prize in Physiology or Medicine". Medical Journal of Australia (Medical Journal of Australia) 183 (11/12): 612–614. Retrieved 2007-01-28.
- Dalziel, Charles F. (1956). The effects of electric shock on man. Washington, D.C. : U.S. Atomic Energy Commission, Office of Health and Safety Series: Safety and fire protection technical bulletin; no. 7.
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- Warwick,K, Gasson,M, Hutt,B, Goodhew,I, Kyberd,P, Schulzrinne,H and Wu,X: “Thought Communication and Control: A First Step using Radiotelegraphy”, IEE Proceedings on Communications, 151(3), pp.185-189, 2004